127638836721 has 32 divisors (see below), whose sum is σ = 208287805440. Its totient is φ = 76605814800.

The previous prime is 127638836711. The next prime is 127638836723.

It is a happy number.

127638836721 is a `hidden beast` number, since 1 + 276 + 3 + 8 + 8 + 367 + 2 + 1 = 666.

127638836721 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 127638836721 - 2⁷ = 127638836593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (127638836723) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2055625 + ... + 2116806.

It is an arithmetic number, because the mean of its divisors is an integer number (6508993920).

Almost surely, 2^127638836721 is an apocalyptic number.

127638836721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

127638836721 is a deficient number, since it is larger than the sum of its proper divisors (80648968719).

127638836721 is a wasteful number, since it uses less digits than its factorization.

127638836721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4172554 (or 4172548 counting only the distinct ones).

The product of its digits is 4064256, while the sum is 54.

The spelling of 127638836721 in words is "one hundred twenty-seven billion, six hundred thirty-eight million, eight hundred thirty-six thousand, seven hundred twenty-one".